Hi,
I use the 60 degree mechanical etching bits from Think and Tinker.
They are about $9US each in lots of 10. I have yet to try a CARBIDE
dental bit. See if you can locate one. Make sure it is CARBIDE! The
HHS ones do about 12" and then die. What RPMs and speed are you using?
John
--- In
Homebrew_PCBs@yahoogroups.com, "aussiedude36"
<aussiedude@e...> wrote:
> I modified an old CNC training machine to work with DeskCNC and
have
> been happily engraving PCB's for a while now, however the only bit
> that I have found that works really well is a M99 carbide spade bit
> from http://www.northbaytechnical.com/ . These bits work great but
> are a bit spendy at about US $15.00 each. Does anyone have
> suggestions/different suppliers etc they can recommend? I don't
think
> self sharpening works too well for me as the bits are just too darn
> small and brittle. BTW the size of track you can get down to with
> these bits seems to be 8 thou or smaller, pretty impressive I think.